Proper ventilation has become a necessity both at home and in the workplace. Most commonly, a homeowner will require proper ventilation when painting a room or finishing a floor within his or her home. Ventilation, especially the ability to allow for a cross-breeze within the work area, will alleviate the build-up of toxic fumes while allowing the paint or finish to dry quicker.
Factories and construction sites are also in need of proper ventilation. Factories manufacture chemicals in extremely large quantities, and must prevent build-up of fumes. Construction sites are most always filled with dust and debris, which if inhaled, can be extremely hazardous to a worker's health.
Many improvements in windows have occurred over the years, which have gone beyond simple vertical movement. Today, windows can be opened along a vertical axis, similar to opening a door. Also, windows can be extended off their frames, similar to opening a hatch on a boat. However, most of the improvements with windows have made use of a device in the channel of a window frame that allows the window sash to pivot. Thus, the window can be tilted outward from the top or bottom depending where the pivotable sash is placed. Also, these devices have allowed users to maintain a window in a tilted position.
The use of a pivotable window sash has had many advantages. Windows can be easily replaced if the pane becomes cracked. Also, because they are easily removable, the windows can be taken out to be cleaned. Or, the window can be tilted and maintained in a fixed position for cleaning.
U.S. Pat. No. 4,610,108 discloses a device for maintaining a tilt-out window in a fixed position. However, the cam member which engages the window sash is very difficult to turn because of the great compressive force placed on it by the spring member. Also, the serrated portion of the spring member may strip the vinyl surface of the window channel if the window begins to slip, or force is placed on the window when it is in the tilted position.
One type of pivotable sash balance brake or shoe is shown in U.S. Pat. No. 5,371,971. This patent relates to a lock where the pivot pin extends outwardly from the window sash. The sash balance brake is disposed within a track in the window frame and includes a cam rotatably disposed within an expandable housing. The pivot pin has a collar for lateral engagement with the cam to prevent the window frame from bowing away from the window sash, thereby maintaining the window frame substantially square. The cam in this lock is disposed within an expandable housing. The pivot pin is received by the U-shaped cavity of the cam, such that rotation of the pivot pin upon pivoting of the sashes rotates the cam, thereby expanding the expandable housing to thereby lock the housing in its place and in its respective track. The cam also has a solid circular covering corresponding generally to the shape of a side housing opening, which is also substantially circular.
Another type of pivotable sash balance brake or shoe is found in Ashland's U.S. Pat. No. 5,806,243. In this patent the sash balance brake assembly comprises a rotor having a rotor camming surface and being rotatable about a rotor axis. A slider body is placed in one of the channels for coupling to one of the sash balance assemblies. The slider body includes means for rotatably supporting the rotor such that the camming surface is directed outwardly towards the respective outer wall. A bolt is provided having a bolt camming surface in operative engagement with the rotor camming surface, such that rotation of the rotor moves the bolt along the rotor axis and into engagement with the outer wall.